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2012-06-17 FCST: ND/SD/NE

With the forecast arrival of some potent midlevel flow and troughing in the northern plains this coming week, it looks like we may have a shot at a few chases. Our first chance might be Sunday with a "day before the day" type event. The GFS has been consistently showing some 30-50 knot midlevel flow nosing in the Dakotas along with sufficient moisture return. The NAM has picked up on this now and is showing a small surface low on the SD/ND border. If that materializes, the moisture convergence and enhanced lift should compliment the modest upper level dynamics, and we should see a few storms off the nose of that surface low and maybe where the midlevel flow bisects the trailing dryline. Cap looks to be wide open by 0z Monday with both models initiating convection. Deep layer shear at 30-50 knots and sufficient mid 60's dews for moderate instability should support supercells, and with a nice veering wind profile, and a strengthening low level jet a few tornadoes look more than possible. Given what looks to be isolated storm coverage, I wouldn't expect SPC to go very high on the probabilities and we shouldn't see anything along the lines of what we had two years on that date, but it could be a great chase day in the Dakotas with some isolated photogenic supercells, maybe a tornado, and a great start to what looks to be an active chase week.
 
Per latest NAM. . .

Eastern SD looks quite nice where speed and turning are concerned in regards to shear. Relatively good sized hodographs.

Big concern is capping. Looks to be in breakable range if you look at 700s.

NAM also has the dewpoints slacking off pretty bad further east towards MN border... resulting in narrow corridor of good CAPE. Though I'm a bit skeptical on this development.
 
Good call on this a few days out, guys... I hadn't really looked at it too much.

My main concern is moisture for today. You can see as of about 15Z that there are lower to mid-60s Tds moving north, but upper level moisture is still a concern. Could still be some nifty storms, however, especially if the mid-level forecasted moisture returns as abundantly as the 12Z NAM is showing... otherwise I'd imagine a bust day may end up partially due to scoured moisture in the mid-levels. Unfortunately I am grounded due to Father's Day today... so best of luck to you guys going out there!
 
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